The thermocouple is part of the pilot burnerassembly and connects to the gas control valve on the outside ofthe water heater. It is a simple device that converts theheat from a burning flame into a small electrical current, allowingit to work like a switch to control the flow of gas from the gassupply valve.

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Similarly, how do you test a thermocouple on a water heater?

If the pilot light doesn't stay lit, check thegas water heater thermocouple by keeping the pilot buttondepressed. Measure the current by using the multimeter device, seton millivolts. One probe of the meter should be connected to thecopper sheath of the thermocouple and the other to the gasvalve.

Also, how do you replace a thermocouple on a water heater? How to Replace a Water Heater's Thermocouple

1. Turn off the gas supply.
2. Unfasten the three nuts that hold the thermocouple and the twogas tubes to the valve.
3. Detach the thermocouple from the burner.
4. Install the new one the same way that you removed the oldone.
5. Turn the gas back on and follow the lighting instructions onthe water heater.

Similarly, are water heater thermocouples universal?

Universal thermocouples come in lengths from 15to 36 inches. An 18 or 24 inch will suffice for all residentialwater heaters using universal kits. Almost all olderwaters heaters and many of the newer style units with a sealedburner compartment and a viewing window will use thisthermocouple.

Can you clean a thermal coupler?

Remove Thermocouple from pilot assembly, usingsteel wool or emery cloth to lightly clean the tip removingany soot or build up that might have accorded due to an improperpilot flame. Using an eraser from a pencil; clean thethreads of the nut that connects the Thermocouple to thecontrol valve and then re-tighten.

Related Question Answers

How do you check if a thermocouple is working?

Select the ohms or resistance option on your multimeter.Place one test lead on the side of the thermocoupleand the other to the end that screws into the gas valve.If the thermocouple has proper continuity, a smallresistance reading should be visible on themultimeter.

How much does it cost to replace a thermocouple on a water heater?

The No. 1 cause of pilot lights that won't stay lit is aworn-out thermocouple. It's easy to replace and a newone costs $5 to $10. Rather than trying to unfasten thethermocouple inside the water heater's burningchamber, it's easier to remove the whole burner andthermocouple assembly.

What does it mean when your pilot light keeps going out?

Usually, a problem with the thermocouple causesthe pilot light to go out. The thermocouple isthe small copper rod that the pilot light hits.The thermocouple's job is to shut a gas safety valve ifthe pilot light goes out. That's important because gas isalways being supplied to the pilot to keep the flamelit.

How long does a thermocouple last?

Thermocouples can last several years, butthey don't typically last as long as the furnaceitself. If the pilot remains lit, but the main furnace doesn't staylit, it's time to replace the thermocouple. Replacementthermocouples are in stock at most hardware and homeimprovement stores.

How does a thermocouple work in a water heater?

The thermocouple is part of the pilot burnerassembly and connects to the gas control valve on the outside ofthe water heater. It is a simple device that converts theheat from a burning flame into a small electrical current, allowingit to work like a switch to control the flow of gas from thegas supply valve.

How do you light a hot water heater with an igniter?

Illuminate the pilot burner with the flashlight. Turnthe gas regulator valve's knob to “Pilot,” press downon it and hold it down. This starts the flow of gas to the pilotburner. On some water heater models, you press and hold downa separate red button to start the pilot burner gasflow.

How does a gas hot water heater work?

Anatomy of a Gas Water Heater The gas water heater works by a law of physicscalled convection which loosely paraphrased, states that heatrises. Cold water is supplied to the tank and injected atthe bottom of the tank through a dip tube. The denser coldwater stays there and is heated by the gasburner.

What is the difference between Type K and Type J thermocouples?

Type J Thermocouple: The type J is alsovery common. It has a smaller temperature range and a shorterlifespan at higher temperatures than the Type K. It isequivalent to the Type K in terms of expense andreliability. Thermocouple grade wire, -346 to 1,400F (-210to 760C) Extension wire, 32 to 392F (0 to 200C)

How close should a thermocouple be to the flame?

A proper pilot flame should be blue with a yellowtip and should be strong enough to cover about 1/2 inch atthe end of the thermocouple tip. If the flame is toostrong and improperly adjusted, it will be blue but may be noisyand lift off the thermocouple, causing improper furnaceoperation.

Are thermocouples universal?

Lead length universal gas thermocouple isdesigned for gas furnaces and 30 millivolt systems. The element isbuilt for reliability and long life and designed as a replacementfor existing universal gasthermocouples.

Do all gas water heaters have thermocouples?

Not all water heaters use a thermocouple.Some of the more recent models use a mercury sensor to shut off thegas valve. An electric water heaters don't usegas at all, and therefore doesn't need anykind of emergency gas shut off. Thermocouples canfail and require replacement.

Does length of thermocouple matter?

The length of a thermocouple has no effecton its measurement accuracy or its ability to transfer the signalto the instrument. In other words, thermocouples do notexperience “voltage drops” or power loss along itslength as a high current power line mightpossess.

What does it mean when your hot water heater won't stay lit?

Thermocouple. If your gas water heater doesn'tstay lit, you may have a defective thermocouple. Mostgas fired water heaters use a standing pilotto ignite the main burner. The gas for thepilot assembly is supplied by the main gasvalve and is monitored by thethermocouple.